| Project/Area Number |
15360503
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nuclear engineering
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| Research Institution | Tokyo University of Marine Science and Technology |
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Principal Investigator |
TOMOJI Takamasa Tokyo University of Marine Science and Technology, Faculty of Marine Technology, Professor, 海洋工学部, 教授 (20134851)
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| Co-Investigator(Kenkyū-buntansha) |
MOTODA Shinichi Tokyo University of Marine Science and Technology, Faculty of Marine Technology, Associate professor, 海洋工学部, 助教授 (10190969)
HAZUKU Tatsuya Tokyo University of Marine Science and Technology, Faculty of Marine Technology, Associate professor, 海洋工学部, 助教授 (60334554)
UEMATSU Susumu National Maritime Research Institute, Advanced Maritime Transport Technology Department, Senior Researcher, 輸送高度化研究領域, 上席研究員
OKAMOTO Koji The University of Tokyo, Dept.Quantum Engineering & Systems Science, Professor, 大学院・工学系研究科, 教授 (80204030)
FURUYA Masahiro Central Research Institute of Electric Power Industry, Nuclear Technology Research Laboratory, Senior Researcher, 原子力技術研究所, 主任研究員 (80371342)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥13,300,000 (Direct Cost: ¥13,300,000)
Fiscal Year 2004: ¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 2003: ¥7,300,000 (Direct Cost: ¥7,300,000)
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| Keywords | Corrosion / Radiation / Surface / Activation / Nuclear / Reactor / Metal / Oxide |
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| Research Abstract |
When a semiconductor film is irradiated by γ-ray, excited electrons are transferred to a base metal in contact with the film, resulting in a drop of corrosion potential. This study proposes a corrosion mitigation method based on radiation induced surface activation(RISA) phenomena by supplying γ-rays from outside the material, or based on a self-excited methodology activating the film and/or the base metal. The results of the study revealed that electrons in the oxide film were activated by γ-ray irradiation and transferred from the oxide to the adjacent base metal. This made the corrosion potential of the metal less noble through a process in which the radiation induced a surface activation phenomenon, even in Zirconium oxide (ZrO_2) films which had large band gap energies. The mitigating method for the corrosion of metals was developed by utilizing this effect. The method involved external γ-rays irradiation introduced by activation of oxide films and/or base metals corrosion potential of ZrO_2 coated SUS304L was shifted down to the range between 90 mV and 300 mV vs. SSE by γ-ray irradiation. The corrosion potential was further shifted down to 600 mV when a CoCr intermediate layer was inserted between the ZrO_2 spray coating film and the SUS304L base metal. Iron specimens with a spray coating film of TiO_2,ZrO_2, and Al_2O_3 were immersed in a 3 wt% sodium chloride aqueous solution. Pitting and general corrosion were suppressed on all three specimens irradiated with γ-rays.
These results clearly show that the corrosion potential of stainless steel could be less noble up to a level of -600 mV vs. SSE with this methodology and these processes would have a remarkable effect in mitigating the corrosion of stainless steels used in internal structures of nuclear reactors.
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